JP5915638B2 - Toner for electrostatic image development - Google Patents

Description

  The present invention relates to an electrostatic charge image developing toner used for electrophotographic image formation.

In recent years, in order to further save energy in an electrophotographic image forming apparatus, an electrostatic image developing toner (hereinafter also simply referred to as “toner”) that is thermally fixed at a lower temperature is required. ing. In toners, low-temperature fixing can be achieved by lowering the melting temperature and melt viscosity of the binder resin, but lowering the melt temperature and melt viscosity lowers heat-resistant storage stability. It is necessary to obtain both sexiness.
In response to such a demand, a toner having a core-shell structure with separated functions, in which a core portion exhibiting low-temperature fixability is coated with a shell layer exhibiting heat-resistant storage properties has been proposed.

  However, when the compatibility between the core resin constituting the core portion and the shell resin constituting the shell layer is high, the shell layer is easily softened, so that the toner particles are fused with each other and sufficient heat-resistant storage stability is obtained. The problem that it cannot be obtained occurs. On the other hand, when the compatibility between the core resin and the shell resin is excessively low, there is a problem that the strength of the fixed image is deteriorated because the shell layer is detached from the core portion.

In order to obtain both low-temperature fixability and heat-resistant storage stability, for example, in Patent Document 1, the compatibility with the shell layer is controlled by including a polyester resin containing a structure derived from isophthalic acid in the core part. Toner is disclosed.
According to such a toner, excellent low-temperature fixability can be obtained due to the sharp melt property of the polyester resin during heat fixing. On the other hand, because the structure derived from isophthalic acid in the polyester resin contained in the core portion provides high compatibility (micro compatibility) with the release agent contained in the core portion, It is possible to suppress the exposure of the mold agent to the surface of the toner particles, and to obtain high compatibility (micro compatibility) at the interface between the core portion and the shell layer due to the structure derived from the isophthalic acid. And high adhesion can be obtained between the core portion and the shell layer. At this time, since the core part and the shell layer are not in a state where the materials are completely mixed with each other, a good heat-resistant storage property can be obtained without the shell layer being detached from the core part while being in an incompatible state.

However, when a polyester resin is used as the binder resin for the toner, the glossiness of the fixed image tends to increase due to a temporary decrease in the viscosity at the time of melting due to the sharp melt property during heat fixing. . For example, in order to make it easier to recognize characters in a character image, it is required that the fixed image is not glaring.
That is, there is a need for a toner that can suppress the glossiness of a fixed image in addition to sufficient low-temperature fixability and excellent heat storage stability. It was difficult to achieve.

Japanese Patent No. 4665707

  The present invention has been made in view of the circumstances as described above, and the object thereof is to obtain both a sufficient low-temperature fixability and excellent heat-resistant storage properties, and a low glossiness. An object of the present invention is to provide a toner for developing an electrostatic image capable of forming a fixed image.

The toner for developing an electrostatic charge image of the present invention has a core-shell structure comprising a core part containing the first polyester resin A and a shell layer containing the second polyester resin B covering the core part. Consisting of toner particles,
The second polyester resin B has at least a metaphenylene skeleton,
The second polyester resin B is an amorphous polyester resin formed by bonding a vinyl polymerization segment and a polyester polymerization segment,
When the content of the metaphenylene skeleton of the first polyester resin A is a (mass%) and the content of the metaphenylene skeleton of the second polyester resin B is b (mass%), the following relational expression (1 ) Is satisfied.
Relational expression (1): 0 ≦ a <b

In the electrostatic image developing toner of the present invention, it is preferable that the first polyester resin A contained in the core portion is a crystalline polyester resin.
In the electrostatic image developing toner of the present invention, the second polyester resin B contained in the shell layer is preferably an amorphous polyester resin.

  In the electrostatic image developing toner of the present invention, the metaphenylene skeleton in the first polyester resin A contained in the core part is preferably derived from isophthalic acid.

  In the toner for developing an electrostatic charge image of the present invention, the metaphenylene skeleton in the second polyester resin B contained in the shell layer is preferably derived from isophthalic acid.

  In the toner for developing an electrostatic charge image of the present invention, the content a of the metaphenylene skeleton of the first polyester resin A contained in the core portion and the meta of the second polyester resin B contained in the shell layer. The difference (ba) in the content b of the phenylene skeleton is preferably 4% by mass or more.

  In the toner for developing an electrostatic charge image of the present invention, the content b of the metaphenylene skeleton of the second polyester resin B contained in the shell layer is preferably 4 to 16% by mass, and more preferably 8 to It is preferable that it is 16 mass%.

  In the electrostatic image developing toner of the present invention, the core portion preferably contains a styrene acrylic resin together with the first polyester resin A.

  According to the toner for developing an electrostatic charge image of the present invention, a core comprising a core portion containing the first polyester resin A and a shell layer containing the second polyester resin B having a high metaphenylene skeleton content. Since the toner particles have a shell structure, sufficient low-temperature fixability and excellent heat-resistant storage stability can be obtained at the same time, and a fixed image with low glossiness can be formed.

  Hereinafter, the present invention will be specifically described.

In the toner of the present invention, the surface of the core part formed by the core resin containing the first polyester resin A has a shell layer formed by the shell resin containing the second polyester resin B having at least a metaphenylene skeleton. Toner particles having a core-shell structure coated with the toner particles.
The content a (mass%) of the metaphenylene skeleton of the first polyester resin A and the content b (mass%) of the metaphenylene skeleton of the second polyester resin B are expressed by the relational expression (1): 0 ≦ a <B is satisfied.

In the present invention, the toner particles having a core-shell structure are not limited to a form in which the shell layer completely covers the core part, but may be a part that covers a part of the core part. The shell layer is preferably in the form of covering the core portion by 80 area% or more.
Moreover, the form in which a part of shell resin which comprises a shell layer forms the domain etc. in the core part may be sufficient.

According to the toner as described above, a toner having a core-shell structure including a core portion containing the first polyester resin A and a shell layer containing the second polyester resin B having a high content of metaphenylene skeleton. Since it consists of particles, sufficient low-temperature fixability and excellent heat-resistant storage stability can be obtained at the same time, and a fixed image with low glossiness can be formed.
This is considered to be due to the following reasons. That is, first, since the content a of the metaphenylene skeleton in the core part is zero or lower than the content b of the metaphenylene skeleton in the shell resin, it has a sharp melt property and melts quickly at the time of heat fixing. Low temperature fixability can be obtained.
On the other hand, when the content ratio b of the metaphenylene skeleton in the shell resin is higher than the content ratio a of the metaphenylene skeleton in the core resin, the compatibility between the core portion and the shell layer is suppressed to be low, and further contained in the shell resin. Further, since the main chain molecules constituting the shell resin can be partially bent by the metaphenylene skeleton, the space occupied by the shell resin molecules becomes large, and the intermolecular distance increases. Therefore, even when the shell layers of the toner particles are in contact with each other, the size of the occupied space makes it difficult to receive intermolecular interactions in the microscopic part, and the fusion between the shell layers of the toner particles is suppressed, resulting in excellent heat resistance. Presumably, storability is obtained.
Further, since the compatibility between the core portion and the shell layer is suppressed to be low, the first polyester resin A partially remains as a domain in the fixed image, so that the toner particles when heat-fixed have an uneven structure. And the unevenness structure along the shape of the toner particles remains in the fixed image due to the low compatibility between the shell layers of the toner particles that is less susceptible to intermolecular interactions at the microscopic part. It is presumed that the smoothness of the surface of the image is suppressed to a low level, and as a result, the glossiness of the formed fixed image is suppressed to a low level.

[Core part]
The core resin forming the core portion contains the first polyester resin A, and it is preferable that the first polyester resin A and the styrene acrylic resin are contained. Styrene acrylic resin is easy to take the structure which can exhibit higher elasticity than polyester resin. And according to the core part containing a highly elastic styrene acrylic resin, the elastic fall of the whole core resin at the time of heat fixing can be suppressed.
The first polyester resin A is either a crystalline polyester resin or an amorphous polyester resin, and the first polyester resin A is preferably a crystalline polyester resin.
The first polyester resin A may be a crystalline vinyl-modified polyester resin formed by bonding a vinyl polymer segment and a polyester polymer segment. According to the core part containing such a vinyl-modified polyester resin, excellent compatibility with the styrene acrylic resin can be obtained when a styrene acrylic resin is used in combination with the core part.

[First polyester resin A]
The content ratio of the first polyester resin A in the core resin is preferably 10 to 100% by mass, and more preferably 10 to 30% by mass in the core resin.
When the content ratio of the first polyester resin A in the core resin is 10% by mass or more, sufficient low-temperature fixability can be reliably obtained. When the content rate of the 1st polyester resin A is 30 mass% or less, the outstanding heat-resistant storage property is obtained reliably.

The first polyester resin A may have a metaphenylene skeleton or may not have a metaphenylene skeleton.
The content a of the metaphenylene skeleton of the first polyester resin A may satisfy the relational expression (1): 0 ≦ a <b in relation to the content b of the metaphenylene skeleton of the second polyester resin B. Specifically, it is preferably 0 to 16% by mass.

  In the present invention, the content of the metaphenylene skeleton of the polyester resin refers to the total mass of the resin material used for synthesizing the polyester resin, that is, in the case of an unmodified polyester resin, the content of polycarboxylic acid components and In order to combine the total mass of the monohydric alcohol components, the polyvalent carboxylic acid component and the polyhydric alcohol component that become the polyester polymerization segment, and the vinyl monomer that becomes the vinyl polymerization segment in the case of a vinyl-modified polyester resin It is the ratio of the mass of the monomer that provides the metaphenylene skeleton to the total mass of the two reactive monomers.

(Crystalline polyester resin)
The crystalline polyester resin is obtained by condensation polymerization of at least a diol component and a dicarboxylic acid component.

  In the present invention, the crystalline polyester resin refers to a polyester resin having a clear endothermic peak rather than a stepwise endothermic amount change in differential scanning calorimetry (DSC). The clear endothermic peak specifically means a peak in which the half-value width of the endothermic peak is within 15 ° C. when measured at a rate of temperature increase of 10 ° C./min in differential scanning calorimetry (DSC). To do.

The diol component for forming the crystalline polyester resin contains an aliphatic diol whose carbon chain is a straight chain having 6 to 12 carbon atoms, and other diols may be used in combination as necessary. In the present invention, a linear aliphatic diol (linear aliphatic diol) means a structure in which OH groups are bonded to both ends.
The diol component is not limited to one type, and two or more types may be mixed and used.

Examples of the straight chain aliphatic diol having 6 to 12 carbon atoms include 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol. 1,11-undecanediol, 1,12-dodecanediol and the like.
As the linear aliphatic diol, it is preferable to use one in which two OH groups are bonded to both ends of the carbon chain.

  Examples of other diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,15. -Other linear fatty acid diols such as pentadecanediol, 1,18-octadecanediol, 1,20-eicosanediol; 2-butene-1,4-diol, 3-hexene-1,6-diol, 4-octene Examples thereof include diols having a double bond such as -1,8-diol.

  When the first polyester resin A has a metaphenylene skeleton, when the metaphenylene skeleton of the first polyester resin A is introduced from the diol component, the diol component that provides the metaphenylene skeleton includes metaxylene Glycol can be used.

The dicarboxylic acid component for forming the crystalline polyester resin includes a linear aliphatic dicarboxylic acid in which the carbon chain excluding the carbon belonging to the carboxyl group is a straight chain having 6 to 12 carbon atoms, and if necessary, other A dicarboxylic acid may be used in combination.
The dicarboxylic acid component is not limited to one type, and two or more types may be mixed and used.

Examples of the linear aliphatic dicarboxylic acid having 6 to 12 carbon atoms include suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, and the like. Is mentioned.
As the linear aliphatic dicarboxylic acid, it is preferable to use one in which two COOH groups are bonded to both ends of the carbon chain.

  Examples of other dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, and 1,16-hexadecanedicarboxylic acid. Examples include acids and other linear fatty acid dicarboxylic acids such as 1,18-octadecanedicarboxylic acid; their lower alkyl esters and acid anhydrides.

When the first polyester resin A has a metaphenylene skeleton, when the metaphenylene skeleton of the first polyester resin A is introduced from a dicarboxylic acid component, the dicarboxylic acid component that provides the metaphenylene skeleton is: Isophthalic acid or 2,7-naphthalenedicarboxylic acid can be used.
When the first polyester resin A has a metaphenylene skeleton, the metaphenylene skeleton is preferably derived from isophthalic acid.

The method for producing the crystalline polyester resin is not particularly limited, and can be produced by using a general polyester polymerization method in which a dicarboxylic acid component and a diol component are reacted in the presence of a catalyst, such as direct polycondensation or ester. It is preferable that the exchange method is used in accordance with the type of monomer.
Examples of catalysts that can be used for the production of crystalline polyester resins include titanium catalysts such as titanium tetraethoxide, titanium tetrapropoxide, titanium tetraisopropoxide, titanium tetrabutoxide, dibutyltin dichloride, dibutyltin oxide, and diphenyltin oxide. And tin catalysts.

  The use ratio of the dicarboxylic acid component to the diol component is preferably an equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] of the diol component and the carboxyl group [COOH] of the dicarboxylic acid component, preferably 1.5. /1-1/1.5, more preferably 1.2 / 1 to 1 / 1.2.

The molecular weight of the crystalline polyester resin measured by gel permeation chromatography (GPC) is preferably a weight average molecular weight (Mw) of 5,000 to 100,000, more preferably 10,000 to 50,000. It is.
When the crystalline polyester resin has a weight average molecular weight (Mw) of 5,000 or more, bleeding of the crystalline polyester resin is suppressed even during storage, and sufficient heat-resistant storage stability is obtained. When the weight average molecular weight (Mw) of the crystalline polyester resin is 100,000 or less, sufficient low-temperature fixability can be obtained.

The molecular weight measurement by GPC was performed as follows. That is, using an apparatus “HLC-8220” (manufactured by Tosoh Corporation) and a column “TSKguardcolumn + TSKgelSuperHZM-M3 series” (manufactured by Tosoh Corporation), while maintaining the column temperature at 40 ° C., tetrahydrofuran (THF) was used as a carrier solvent at a flow rate of 0. The sample to be measured (crystalline polyester resin) was dissolved in tetrahydrofuran to a concentration of 1 mg / ml under a dissolution condition in which treatment was performed for 5 minutes using an ultrasonic disperser at room temperature. A sample solution is obtained by processing with a 2 μm membrane filter, and 10 μL of this sample solution is injected into the apparatus together with the carrier solvent, detected using a refractive index detector (RI detector), and the molecular weight distribution of the measurement sample. Was measured using monodisperse polystyrene standard particles. Calculate using a quantitative curve. As a standard polystyrene sample for calibration curve measurement, molecular weights manufactured by Pressure Chemical Co., Ltd. are 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1 .1 × 10 ⁵ , 3.9 × 10 ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶ , and at least about 10 standard polystyrene samples were measured, and a calibration curve It was created. A refractive index detector was used as the detector.

As the crystalline polyester resin, one having a melting point of 40 to 90 ° C is preferably used, and more preferably 55 to 80 ° C.
When the melting point of the crystalline polyester resin is 40 ° C. or higher, the obtained toner has a high thermal strength and a sufficient heat-resistant storage property is obtained. In addition, since the melting point of the crystalline polyester resin is 90 ° C. or less, the crystalline polyester resin can be quickly melted during thermal fixing to promote fixing on a transfer material, and sufficient low-temperature fixing property can be obtained. It is done.

  Here, the melting point of the crystalline polyester resin is specifically determined by using a differential scanning calorimeter “Diamond DSC” (manufactured by Perkin Elmer Co., Ltd.) and raising the temperature from 0 ° C. to 200 ° C. at an elevation rate of 10 ° C./min. Measurement through a temperature increasing process, a cooling process for cooling from 200 ° C. to 0 ° C. at a cooling rate of 10 ° C./min, and a second temperature increasing process for increasing the temperature from 0 ° C. to 200 ° C. at a lifting speed of 10 ° C./min. Based on the DSC curve obtained by this measurement (temperature increase / cooling conditions), the melting point is the endothermic peak top temperature derived from the crystalline polyester resin in the first temperature increase process. It is. As a measurement procedure, 3.0 mg of crystalline polyester resin is sealed in an aluminum pan and set in a sample holder of “Diamond DSC”. The reference used an empty aluminum pan.

[Styrene acrylic resin]
The styrene acrylic resin is formed of a styrene monomer and a (meth) acrylic acid ester monomer.

Examples of the styrene monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, p-ethylstyrene, and pn. -Butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2,4- Examples thereof include dimethylstyrene, 3,4-dichlorostyrene, and derivatives thereof.
Examples of (meth) acrylic acid ester monomers include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, and methacrylic acid. Examples include butyl, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and the like.
These can be used individually by 1 type or in combination of 2 or more types.

In addition, as a polymerizable monomer for forming a styrene acrylic resin, a monomer having the following vinyl group together with the above styrene monomer and (meth) acrylic acid ester monomer (hereinafter, “ Vinyl monomer ")) can also be used.
・ Olefins Ethylene, propylene, isobutylene, etc .;
・ Vinyl esters Vinyl propionate, vinyl acetate, vinyl benzoate, etc .;
・ Vinyl ethers Vinyl methyl ether, vinyl ethyl ether, etc .;
・ Vinyl ketones Vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone, etc .;
N-vinyl compounds N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidone, etc .;
・ Others Vinyl compounds such as vinyl naphthalene and vinyl pyridine, acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide.

Moreover, as a polymerizable monomer for forming a styrene acrylic resin, the following ions such as a carboxy group and a phosphate group, together with the above styrene monomer and (meth) acrylate monomer, are used. Those having an ionic dissociation group can also be used.
・ Carboxy group-containing vinyl monomer (meth) acrylic acid such as acrylic acid, methacrylic acid, α-ethylacrylic acid, crotonic acid, and α-alkyl derivatives or β-alkyl derivatives; fumaric acid, maleic acid, citraconic acid Unsaturated dicarboxylic acids such as itaconic acid; unsaturated dicarboxylic acid monoester derivatives such as succinic acid monoacryloyloxyethyl ester, succinic acid monoacryloyloxyethylene ester, phthalic acid monoacryloyloxyethyl ester, phthalic acid monomethacryloyloxyethyl ester Such.
-Vinyl monomer having a phosphate group Acid phosphooxyethyl methacrylate, etc.

Further, as the polymerizable monomer for forming the styrene acrylic resin, the following polyfunctional vinyls may be used together with the above styrene monomer and (meth) acrylic acid ester monomer. it can.
-Polyfunctional vinyls Ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, and the like.

As for the molecular weight measured by the gel permeation chromatography (GPC) of a styrene acrylic resin, it is preferable that a weight average molecular weight (Mw) is 20,000-60,000.
When the weight average molecular weight (Mw) of the styrene acrylic resin is 20,000 or more, sufficient heat-resistant storage stability is obtained. Sufficient low-temperature fixability can be obtained when the weight average molecular weight (Mw) of the styrene acrylic resin is 60,000 or less.

  The molecular weight measurement by GPC of styrene acrylic resin is performed in the same manner as described above except that styrene acrylic resin is used as a measurement sample.

The glass transition point of the styrene acrylic resin is preferably 20 to 40 ° C.
When the glass transition point of the styrene acrylic resin is 20 ° C. or higher, the obtained toner has a high thermal strength, and sufficient heat-resistant storage stability is obtained. In addition, when the glass transition point of the styrene acrylic resin is 40 ° C. or less, sufficient low-temperature fixability can be obtained.

  Here, the glass transition point of the styrene acrylic resin is a value measured by a method (DSC method) defined in ASTM (American Society for Testing and Materials) D3418-82 using a styrene acrylic resin as a measurement sample.

[Shell layer]
The shell resin forming the shell layer contains a second polyester resin B having a metaphenylene skeleton, and this second polyester resin B is preferably an amorphous polyester resin, and in particular, vinyl. It is preferably an amorphous vinyl-modified polyester resin formed by bonding a polymerized segment and a polyester polymerized segment.

[Second polyester resin B]
The content ratio of the second polyester resin B in the shell resin is preferably 70 to 100% by mass, and more preferably 90 to 100% by mass in the shell resin.
When the content ratio of the second polyester resin B in the shell resin is 70% by mass or more, the effect of suppressing the glossiness in the obtained fixed image is sufficiently obtained.

The content b of the metaphenylene skeleton of the second polyester resin B only needs to satisfy a <b in relation to the content a of the metaphenylene skeleton of the first polyester resin A. Specifically, The difference (ba) between the metaphenylene skeleton content a of the polyester resin A and the metaphenylene skeleton content b of the second polyester resin B is preferably 4% by mass or more.
The content ratio b of the metaphenylene skeleton of the second polyester resin B is larger than the content a of the metaphenylene skeleton of the first polyester resin A, thereby reliably suppressing the compatibility between the core portion and the shell layer. Thus, the heat storage stability and the effect of suppressing the glossiness of the fixed image can be reliably obtained.

The metaphenylene skeleton content b of the second polyester resin B is preferably 4 to 16% by mass, more preferably 8 to 16% by mass.
When the content ratio b of the metaphenylene skeleton of the second polyester resin B is 4% by mass or more, the effect of suppressing the glossiness of the obtained fixed image is sufficiently obtained. On the other hand, when the content b of the metaphenylene skeleton of the second polyester resin B is 16% by mass or less, fusion between the shell layers can be prevented while maintaining the adhesion between the core portion and the shell layer. Excellent heat-resistant storage stability can be obtained.

[Amorphous polyester resin]
In the present invention, the amorphous polyester resin is a polycondensation product of at least a polyhydric alcohol component and a polycarboxylic acid component, and no clear endothermic peak is observed in differential scanning calorimetry (DSC). Polyester resin.

  As the polyvalent carboxylic acid component for forming the amorphous polyester resin, polyvalent carboxylic acid and alkyl esters thereof, acid anhydrides and acid chlorides can be used. Alcohols and their ester compounds and hydroxycarboxylic acids can be used.

  Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, butanediol, diethylene glycol, hexanediol, cyclohexanediol, octanediol, decanediol, dodecanediol, ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, etc. Examples include divalent alcohols; trivalent or higher polyols such as glycerin, pentaerythritol, hexamethylol melamine, hexaethylol melamine, tetramethylol benzoguanamine, and tetraethylol benzoguanamine.

  When the metaphenylene skeleton of the second polyester resin B is introduced from the polyhydric alcohol component, metaxylene glycol can be used as the polyhydric alcohol component that provides the metaphenylene skeleton.

  Examples of the polyvalent carboxylic acid include oxalic acid, succinic acid, maleic acid, adipic acid, β-methyladipic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, fumaric acid. , Citraconic acid, diglycolic acid, cyclohexane-3,5-diene-1,2-dicarboxylic acid, malic acid, citric acid, hexahydroterephthalic acid, malonic acid, pimelic acid, tartaric acid, mucoic acid, phthalic acid, isophthalic acid Acid, terephthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-carboxyphenylacetic acid, p-phenylenediacetic acid, m-phenylenediglycolic acid, p-phenylenediglycolic acid, o-phenylenediglycolic acid, diphenyl Acetic acid, diphenyl-p, p'-dicarbo Divalent carboxylic acids such as acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, anthracene dicarboxylic acid, dodecenyl succinic acid; trimellitic acid, pyromellitic acid And divalent or higher carboxylic acids such as naphthalenetricarboxylic acid, naphthalenetetracarboxylic acid, pyrenetricarboxylic acid, and pyrenetetracarboxylic acid.

When the metaphenylene skeleton of the second polyester resin B is introduced from the polyvalent carboxylic acid component, isophthalic acid can be used as the polyvalent carboxylic acid that provides the metaphenylene skeleton.
The metaphenylene skeleton of the second polyester resin B is preferably derived from isophthalic acid, which is a carboxylic acid, rather than from metaxylene glycol, which is an alcohol.

  Although it does not specifically limit as a manufacturing method of an amorphous polyester resin, It can manufacture according to the manufacturing method similar to the manufacturing method of the above-mentioned crystalline polyester resin.

As for the molecular weight measured by gel permeation chromatography (GPC) of the amorphous polyester resin, the weight average molecular weight (Mw) is preferably 5,000 to 100,000, more preferably 5,000 to 50, 000.
When the weight average molecular weight (Mw) of the amorphous polyester resin is 5,000 or more, compatibility between the amorphous polyester resin and the crystalline polyester resin constituting the core portion occurs during production and storage. Sufficient heat storage stability. When the amorphous polyester resin has a weight average molecular weight (Mw) of 100,000 or less, sufficient low-temperature fixability can be obtained.

  The molecular weight measurement of the amorphous polyester resin by GPC is performed in the same manner as described above except that the amorphous polyester resin is used as a measurement sample.

The glass transition point of the amorphous polyester resin is preferably 40 to 90 ° C, more preferably 45 to 85 ° C.
When the glass transition point of the amorphous polyester resin is 40 ° C. or higher, the obtained toner has a high thermal strength, and sufficient heat-resistant storage stability is obtained. In addition, when the glass transition point of the amorphous polyester resin is 90 ° C. or less, sufficient low-temperature fixability can be obtained.

  The glass transition point of the amorphous polyester resin is a value measured in the same manner as described above except that the amorphous polyester resin was used as a measurement sample.

[Vinyl modified polyester resin]
The vinyl-modified polyester resin is formed by bonding a vinyl polymer segment and a polyester polymer segment, and the vinyl polymer segment may be bonded as a branched chain in the chain of the polyester polymer segment, and constitutes a straight chain. It may be bound to a state. In the case of constituting a straight chain, either the middle or the end of the straight chain may be constituted. However, the vinyl-modified polyester resin in which the vinyl polymer segment is bonded to the terminal of the polyester polymer segment tends to form the domains of the polyester polymer segment and the vinyl polymer segment.
In the present invention, the vinyl-modified polyester resin refers to one having a polyester polymer segment content of 50% by mass or more.

(Vinyl polymerization segment)
The vinyl polymer segment is formed of a vinyl monomer and can be made of a styrene polymer, an acrylic polymer, a styrene-acrylic copolymer, or the like, and is made of a styrene-acrylic copolymer. It is preferable.
Specific examples of the vinyl monomer include those listed as monomers for forming the styrene acrylic resin.

(Polyester polymerization segment)
The polyester polymer segment is an amorphous one formed by a polyvalent carboxylic acid component and a polyhydric alcohol component, and specifically, one having no clear endothermic peak in differential scanning calorimetry (DSC) Say. Specific examples of the monomer (polyhydric carboxylic acid component and polyhydric alcohol component) for forming the polyester polymerization segment are those listed as the monomer for forming the above amorphous polyester resin. Is mentioned.

The content of the vinyl polymerization segment in the vinyl-modified polyester resin is preferably 5 to 30% by mass, and more preferably 5 to 20% by mass.
Specifically, the content ratio of the vinyl polymerization segment is the total mass of the resin material used for synthesizing the vinyl-modified polyester resin, that is, the polyvalent carboxylic acid component and the polyhydric alcohol component that become the polyester polymerization segment, and vinyl. It is the ratio of the mass of the vinyl monomer to the total mass of the total of the vinyl monomer that becomes the polymerization segment and the both reactive monomers for bonding them.
When the content ratio of the vinyl polymerization segment is 5% by mass or more, a highly elastic component can be sufficiently obtained at the time of heat fixing, and excellent high temperature offset resistance can be obtained. On the other hand, when the content ratio of the vinyl polymer segment is 30% by mass or less, the amount of the polyester polymer segment contributing to the low-temperature fixability can be secured, and sufficient low-temperature fixability can be surely obtained.

The weight average molecular weight (Mw) calculated from the molecular weight distribution measured by gel permeation chromatography (GPC) of the vinyl-modified polyester resin is preferably 10,000 to 100,000.
When the weight average molecular weight (Mw) of the vinyl-modified polyester resin is 10,000 or more, it is possible to reliably suppress the gloss of the formed image from becoming excessively high while maintaining the low-temperature fixability. On the other hand, when the weight average molecular weight (Mw) is 100,000 or less, it is possible to reliably prevent the low-temperature fixability from being inhibited while maintaining the heat-resistant storage property.

  The molecular weight measurement by GPC of the vinyl-modified polyester resin is performed in the same manner as described above except that the vinyl-modified polyester resin is used as a measurement sample.

The glass transition point of the vinyl-modified polyester resin is preferably 50 to 75 ° C.
When the glass transition point of the vinyl-modified polyester resin is 50 ° C. or higher, the obtained toner has a high thermal strength, and sufficient heat-resistant storage stability is obtained. On the other hand, when the glass transition point is 75 ° C. or lower, sufficient low-temperature fixability can be obtained.

  The glass transition point of the vinyl-modified polyester resin is a value measured in the same manner as described above except that the vinyl-modified polyester resin is used as a measurement sample.

[Method for producing vinyl-modified polyester resin]
The vinyl-modified polyester resin can be produced by bonding a polyester polymer segment and a vinyl polymer segment via both reactive monomers. Specifically, it can be produced by performing a polycondensation reaction in the presence of a polyvalent carboxylic acid and a polyhydric alcohol at least at any time before, during and after the step of addition polymerization of a vinyl monomer. it can.
Specifically, an existing general scheme can be used. The following three methods are listed as typical methods.
(1) After performing an addition polymerization reaction of a vinyl monomer to form a vinyl polymerization segment, a polycondensation reaction of a polyvalent carboxylic acid and a polyhydric alcohol to form a polyester polymerization segment is performed. A method in which a tri- or higher valent vinyl monomer serving as a crosslinking agent is added to the reaction system to further advance the condensation polymerization reaction.
(2) After the polycondensation reaction of polyvalent carboxylic acid and polyhydric alcohol to form a polyester polymer segment, an addition polymerization reaction of a vinyl monomer to form a vinyl polymer segment is performed, and then necessary According to the method, a trivalent or higher valent vinyl monomer serving as a cross-linking agent is added to the reaction system, and the polycondensation reaction further proceeds under temperature conditions suitable for the polycondensation reaction.
(3) An addition polymerization reaction of a vinyl monomer for forming a vinyl polymerization segment and a polyvalent carboxylic acid and a polyhydric alcohol for forming a polyester polymerization segment under temperature conditions suitable for the addition polymerization reaction. After the polycondensation reaction is carried out in parallel and the addition polymerization reaction is completed, a trivalent or higher valent vinyl monomer as a cross-linking agent is added to the reaction system as necessary, under temperature conditions suitable for the polycondensation reaction. A method of further proceeding the condensation polymerization reaction.

  Both reactive monomers are added together with polyvalent carboxylic acid / polyhydric alcohol and / or vinyl monomer.

Both reactive monomers have at least one functional group selected from the group consisting of a hydroxyl group, a carboxy group, an epoxy group, a primary amino group and a secondary amino group in the molecule, preferably a hydroxyl group and / or a carboxy group. It is preferably a compound having a group, more preferably a carboxy group and an ethylenically unsaturated bond, that is, a vinyl carboxylic acid. Specific examples of the both reactive monomers include, for example, acrylic acid, methacrylic acid, fumaric acid, maleic acid and the like, and these hydroxyalkyl (C1-3) esters may be used. From this viewpoint, it is preferable to use acrylic acid, methacrylic acid and fumaric acid.
In addition, it is preferable to use a monovalent vinyl carboxylic acid as a bi-reactive monomer rather than a polyvalent vinyl carboxylic acid from the viewpoint of toner durability. This is probably because the reactivity between the monovalent vinyl-based carboxylic acid and the vinyl monomer is high, so that it can be easily hybridized. On the other hand, when a dicarboxylic acid such as fumaric acid is used as the bireactive monomer, the durability of the toner is slightly inferior. This is presumably because the reactivity between the dicarboxylic acid and the vinyl monomer is low and it is difficult to form a uniform hybrid, so that it takes a domain structure.

  The amount of the both reactive monomers used is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the total amount of vinyl monomers from the viewpoint of improving the low temperature fixability, high temperature offset resistance and durability of the toner. -8 parts by mass is more preferable, 0.3-8 parts by mass is preferable, and 0.5-5 parts by mass is more preferable with respect to 100 parts by mass of the total amount of the polyvalent carboxylic acid and the polyhydric alcohol.

  The addition polymerization reaction can be performed by a conventional method in the presence of a radical polymerization initiator, a crosslinking agent, or the like, in an organic solvent or in the absence of a solvent, but the temperature condition is preferably 110 to 200 ° C., and 140 to 180. ° C is more preferred. Examples of the radical polymerization initiator include dialkyl peroxide, dibutyl peroxide, butyl peroxy-2-ethylhexyl monocarboxylic acid and the like, and these can be used alone or in combination of two or more.

  The condensation polymerization reaction can be performed, for example, in an inert gas atmosphere at a temperature of 180 to 250 ° C., but is preferably performed in the presence of an esterification catalyst, a polymerization inhibitor, or the like. Examples of the esterification catalyst include tin (II) compounds having no Sn—C bond, such as dibutyltin oxide, titanium compounds, and tin octylate, and these may be used alone or in combination. it can.

[Ratio of core resin to shell resin]
The content ratio of the shell resin in the binder resin composed of the core resin and the shell resin constituting the toner particles is preferably 5 to 50% by mass, and more preferably 10 to 40% by mass.
When the content ratio of the shell resin in the binder resin is 50% by mass or less, the low-temperature fixability by the first polyester resin A constituting the core portion can be sufficiently obtained. On the other hand, when the content ratio of the shell resin in the binder resin is 5% by mass or more, excellent heat-resistant storage stability can be reliably obtained.

[Configuration of toner particles]
In the toner particles according to the present invention, in addition to the resin (binder resin) constituting the core part and the shell layer, an internal additive such as a colorant, a release agent, and a charge control agent is contained as necessary. May be.
The colorant, the release agent, and the charge control agent may each be contained in the core part, may be contained in the shell layer, or may be contained in both. Is preferably contained in the core.

[Colorant]
As the colorant, generally known dyes and pigments can be used.
As a colorant for obtaining a black toner, various known materials such as carbon black such as furnace black and channel black, magnetic materials such as magnetite and ferrite, dyes, and inorganic pigments containing nonmagnetic iron oxide are arbitrarily selected. Can be used.
As the colorant for obtaining a color toner, known ones such as dyes and organic pigments can be arbitrarily used. Specifically, examples of the organic pigment include C.I. I. Pigment Red 5, 48: 1, 48: 2, 48: 3, 53: 1, 57: 1, 81: 4, 122, 139, 144, 149, 166, 177, 178, 222, 238, 269, C.I. I. Pigment Yellow 14, 17, 74, 93, 94, 138, 155, 180, 185, C.I. I. Pigment Orange 31 and 43, C.I. I. Pigment Blue 15: 3, 60, 76, and the like. Examples of the dye include C.I. I. Solvent Red 1, 49, 52, 58, 68, 11, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 69, 70, 93, 95 and the like.
The colorant for obtaining the toner of each color can be used singly or in combination of two or more for each color.
It is preferable that the content rate of a coloring agent is 1-20 mass parts with respect to 100 mass parts of binder resin, More preferably, it is 4-15 mass parts.

〔Release agent〕
The release agent is not particularly limited, and various known waxes can be used. For example, polyolefin waxes such as polyethylene wax and polypropylene wax, branched hydrocarbon waxes such as microcrystalline wax, and paraffins. Long-chain hydrocarbon waxes such as wax and sazol wax, dialkyl ketone waxes such as distearyl ketone, carnauba wax, montan wax, behenate behenate, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, penta Ester wacks such as erythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanediol distearate, tristearyl trimellitic acid, distearyl maleate , Ethylenediamine behenyl amide, an amide-based waxes such as trimellitic acid tristearyl amide.
The content ratio of the release agent is usually 1 to 30 parts by mass, more preferably 5 to 20 parts by mass with respect to 100 parts by mass of the binder resin. When the content ratio of the release agent is within the above range, sufficient fixing separation property can be obtained.

[Charge control agent]
Various known compounds can be used as the charge control agent.
The content ratio of the charge control agent is usually 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the binder resin.

[Toner softening point]
The softening point of the toner is preferably 70 to 120 ° C., more preferably 80 to 110 ° C., from the viewpoint of obtaining low temperature fixability for the toner.

The softening point of the toner is measured by a flow tester shown below.
Specifically, first, in an environment of 20 ° C. and 50% RH, 1.1 g of a sample (toner) was placed in a petri dish and left flat for 12 hours or more, and then a molding machine “SSP-10A” (Shimadzu) Pressed with a force of 3820 kg / cm ² for 30 seconds to produce a cylindrical molded sample having a diameter of 1 cm. Then, the molded sample was subjected to a flow tester “24 ° C. and 50% RH in a flow tester“ CFT-500D "(manufactured by Shimadzu Corporation), with a load of 196 N (20 kgf), a starting temperature of 60 ° C., a preheating time of 300 seconds, and a heating rate of 6 ° C./min (1 mm diameter × 1 mm) more, extruded from the time of preheating ends with piston diameter 1 cm, offset method temperature T _offset measured by setting the offset value 5mm at a melt temperature measurement method of temperature ramps is the softening point That.

[Average toner particle size]
The average particle diameter of the toner of the present invention is preferably 3 to 9 μm, and more preferably 3 to 8 μm, for example, on a volume basis median diameter. This particle size can be controlled by the concentration of the coagulant used, the addition amount of the organic solvent, the fusing time, the composition of the polymer, and the like, for example, when the emulsion aggregation method described later is employed.
When the volume-based median diameter is in the above range, the transfer efficiency is increased, the image quality of halftone is improved, and the image quality of fine lines and dots is improved.

  The volume-based median diameter of the toner particles is measured and calculated using a measuring device in which “Multisizer 3” (manufactured by Beckman Coulter) is connected to a computer system equipped with data processing software “Software V3.51”. Is. Specifically, 0.02 g of toner is added to 20 mL of a surfactant solution (for example, a surfactant solution obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing toner particles). Then, ultrasonic dispersion is performed for 1 minute to prepare a toner dispersion, and this toner dispersion is placed in a beaker containing “ISOTON II” (manufactured by Beckman Coulter) in a sample stand. Pipet until the indicated concentration is 8%. Here, a reproducible measurement value can be obtained by setting the concentration range. In the measurement apparatus, the measurement particle count is 25000, the aperture diameter is 50 μm, the frequency value is calculated by dividing the measurement range of 1 to 30 μm into 256, and the volume integrated fraction is 50 % Particle diameter is defined as the volume-based median diameter.

[Average circularity of toner particles]
The toner of the present invention preferably has an average circularity of 0.930 to 1.000, more preferably 0.940 to 0, from the viewpoint of improving the transfer efficiency of the individual toner particles constituting the toner. .995.

In the present invention, the average circularity of toner particles is measured using “FPIA-2100” (manufactured by Sysmex).
Specifically, the sample (toner particles) is blended with an aqueous solution containing a surfactant, subjected to ultrasonic dispersion treatment for 1 minute to disperse, and then subjected to measurement conditions HPF by “FPIA-2100” (manufactured by Sysmex). In the (high-magnification imaging) mode, photographing is performed at an appropriate density of 3,000 to 10,000 HPF detections, and the circularity of each toner particle is calculated according to the following formula (T). Calculated by adding the degree and dividing by the total number of toner particles.
Formula (T): Circularity = (perimeter of a circle having the same projection area as the particle image) / (perimeter of the particle projection image)

[Toner Production Method]
Examples of the method for producing the toner of the present invention include kneading / pulverization method, suspension polymerization method, emulsion polymerization method, emulsion aggregation method, emulsion polymerization aggregation method, miniemulsion polymerization aggregation method, encapsulation method, and other known methods. In particular, it is preferable to use an emulsion aggregation method in which toner particles are obtained by aggregating and fusing the fine particles of the resin constituting the binder resin.

  In the emulsion aggregation method, a dispersion of fine particles of resin constituting the binder resin is mixed with a fine particle dispersion of other toner particle constituents as necessary, and the repulsive force on the surface of the fine particles by pH adjustment and the electrolyte body Aggregate slowly while balancing with the cohesive force due to the addition of the coagulant, and perform association while controlling the average particle size and particle size distribution, and at the same time, heat-stir and fuse the fine particles to control the shape Is a method for producing toner particles.

(External additive)
The above toner particles can constitute the toner of the present invention as they are, but in order to improve fluidity, chargeability, cleaning properties, etc., a fluidizing agent that is a so-called post-treatment agent is added to the toner particles. An external additive such as a cleaning aid may be added to constitute the toner of the present invention.

As the post-treatment agent, for example, inorganic oxide fine particles composed of silica fine particles, alumina fine particles, titanium oxide fine particles, etc., inorganic stearate compound fine particles such as aluminum stearate fine particles, zinc stearate fine particles, or strontium titanate, titanium Inorganic titanic acid compound fine particles such as zinc acid are listed. These can be used individually by 1 type or in combination of 2 or more types.
These inorganic fine particles are preferably subjected to surface treatment with a silane coupling agent, a titanium coupling agent, a higher fatty acid, silicone oil or the like in order to improve heat-resistant storage stability and environmental stability.

  The total amount of these various external additives added is 0.05 to 5 parts by mass, preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the toner. In addition, various external additives may be used in combination.

  According to the toner of the present invention, core-shell toner particles comprising a core portion containing the first polyester resin A and a shell layer containing the second polyester resin B having a high metaphenylene skeleton content. Therefore, it is possible to obtain both a sufficiently low-temperature fixability and excellent heat-resistant storage stability, and it is possible to form a fixed image with a low glossiness.

(Developer)
The toner of the present invention can be used as a magnetic or non-magnetic one-component developer, but may be mixed with a carrier and used as a two-component developer.
As the carrier, for example, magnetic particles made of conventionally known materials such as metals such as iron, ferrite and magnetite, and alloys of these metals with metals such as aluminum and lead can be used. Among these, ferrite particles Is preferably used. As the carrier, a coated carrier in which the surface of magnetic particles is coated with a coating agent such as a resin, a resin-dispersed carrier in which a magnetic fine powder is dispersed in a binder resin, or the like may be used.
The carrier preferably has a volume average particle diameter of 15 to 100 μm, more preferably 25 to 80 μm.

[Image forming apparatus]
The toner of the present invention can be used in a general electrophotographic image forming method. As an image forming apparatus in which such an image forming method is performed, for example, a photosensitive member that is an electrostatic latent image carrier, A charging means for applying a uniform potential to the surface of the photoconductor by corona discharge having the same polarity as that of the toner, and an electrostatic latent image by performing image exposure on the surface of the uniformly charged photoconductor based on image data. An exposure means for forming an image; a developing means for conveying the toner to the surface of the photoreceptor to visualize the electrostatic latent image to form a toner image; and passing the toner image through an intermediate transfer member as necessary. For example, a transfer unit that transfers to a transfer material and a fixing unit that heat-fixes the toner image on the transfer material can be used.
The toner of the present invention can be suitably used at a relatively low temperature where the fixing temperature (the surface temperature of the fixing member) is 100 to 200 ° C.

  As mentioned above, although embodiment of this invention was described concretely, embodiment of this invention is not limited to said example, A various change can be added.

  Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto.

[Preparation Example of Aqueous Dispersion [1] of Styrene Acrylic Resin Fine Particles]
(First stage polymerization)
A 1 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe and a nitrogen introducing device was charged with a solution obtained by dissolving 1.5 parts by mass of polyoxyethylene (2) sodium dodecyl sulfate in 560 parts by mass of ion-exchanged water, The internal temperature was raised to 80 ° C. while stirring at a stirring speed of 300 rpm under a nitrogen stream. After the temperature increase, a solution prepared by dissolving 1.9 parts by mass of potassium persulfate in 37 parts by mass of ion-exchanged water was added, and the temperature was again set to 80 ° C.
-Styrene 113 parts by mass-n-butyl acrylate 32 parts by mass-A monomer mixture consisting of 13.6 parts by mass methacrylic acid was added dropwise over 1 hour, followed by heating and stirring at 90 ° C for 2 hours for polymerization. In this way, a resin fine particle dispersion [a] was prepared.

(Second stage polymerization)
A 5 L reaction vessel equipped with a stirrer, temperature sensor, cooling pipe and nitrogen introducing device is charged with a solution obtained by dissolving 7.4 parts by mass of polyoxyethylene (2) sodium dodecyl ether sulfate in 970 parts by mass of ion-exchanged water. , After heating to 98 ° C., 285 parts by mass of a resin fine particle dispersion [a],
Styrene 284 parts by mass n-butyl acrylate 92 parts by mass methacrylic acid 15.7 parts by mass n-octyl-3-mercaptopropionate 4.2 parts by mass "HNP-0190" (manufactured by Nippon Seiwa Co., Ltd.) A solution prepared by dissolving 120 parts by mass of a monomer mixture solution at 90 ° C. was added, and the mixture was dispersed for 1 hour by a mechanical disperser “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path. A dispersion containing emulsified particles (oil droplets) was prepared.
Next, an initiator solution prepared by dissolving 6.6 parts by mass of potassium persulfate in 126 parts by mass of ion-exchanged water is added to this dispersion, and the system is heated and stirred at 84 ° C. for 1 hour to perform polymerization. In this way, a resin fine particle dispersion [b] was prepared.

(3rd stage polymerization)
Furthermore, a solution in which 12 parts by mass of potassium persulfate was dissolved in 290 parts by mass of ion-exchanged water was added, and under a temperature condition of 82 ° C.,
-Styrene 390 mass parts-n-butyl acrylate 180 mass parts-Methacrylic acid 30 mass parts-n-octyl-3- mercaptopropionate 8.6 mass parts monomer mixture liquid was dripped over 1 hour. After completion of the dropwise addition, polymerization was carried out by heating and stirring for 2 hours, followed by cooling to 28 ° C., thereby obtaining an aqueous dispersion [1] of styrene acrylic resin fine particles by styrene acrylic resin.
With respect to the aqueous dispersion [1] of the obtained styrene acrylic resin fine particles, the glass transition point (Tg) of the styrene acrylic resin fine particles is 50 ° C., the volume-based median diameter is 220 nm, and the weight average molecular weight (Mw) is 59,500. there were.

[Preparation Example of Aqueous Dispersion of Crystalline Polyester Resin Fine Particles [C1]]
(1) Synthesis of crystalline polyester resin In a 5 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube and a nitrogen introducing device, 300 parts by mass of polyvalent carboxylic acid: sebacic acid (molecular weight 202.25) and polyvalent Alcohol: 170 parts by mass of 1,6-hexanediol (molecular weight 118.17) was charged, and while the system was stirred, the internal temperature was raised to 190 ° C. over 1 hour, and the system was uniformly stirred. After confirming that it was present, Ti (OBu) ₄ was added as a catalyst in an amount of 0.003% by mass relative to the charged amount of polyvalent carboxylic acid. Thereafter, the internal temperature is raised from 190 ° C. to 240 ° C. over 6 hours while distilling off the generated water, and the dehydration condensation reaction is continued over 6 hours under the condition of a temperature of 240 ° C. for polymerization. As a result, a crystalline polyester resin [C1] was obtained.
The crystalline polyester resin [C1] had a melting point (Tm) of 66.8 ° C. and a number average molecular weight (Mn) of 6,300.

(2) Preparation of Aqueous Dispersion of Crystalline Polyester Resin Fine Particles Crystalline polyester resin [C1] 30 parts by mass are melted and left in a molten state with respect to an emulsification disperser “Cavitron CD1010” (manufactured by Eurotech Co., Ltd.). It was transferred at a transfer rate of 100 parts by mass per minute. At the same time as the transfer of the crystalline polyester resin [C1] in the molten state, 70 mass parts of reagent ammonia water was diluted with ion-exchanged water in the aqueous solvent tank with respect to the emulsifying disperser, but the concentration was 0.37 mass%. The diluted ammonia water was transferred at a transfer rate of 0.1 liter per minute while being heated to 100 ° C. with a heat exchanger. Then, by operating this emulsification disperser under the conditions of a rotor rotation speed of 60 Hz and a pressure of 5 kg / cm ² , an aqueous system of crystalline polyester resin fine particles having a volume-based median diameter of 200 nm and a solid content of 30 parts by mass. A dispersion [C1] was prepared.

[Preparation example of aqueous dispersion [A1] of vinyl-modified polyester resin fine particles]
(1) Synthesis of vinyl-modified polyester resin In a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple,
Bisphenol A propylene oxide 2 mol adduct 288 parts by mass Isophthalic acid 83 parts by mass Trimellitic acid 26 parts by mass Fumaric acid 14 parts by mass Esterification catalyst (tin octylate) 1.5 parts by mass Reaction, further reaction at 8 kPa for 1 hour, cooling to 160 ° C.,
Acrylic acid 5 parts by mass Styrene 75 parts by mass Butyl acrylate 26 parts by mass Polymerization initiator (di-t-butyl peroxide) A mixture of 16 parts by mass was added dropwise with a dropping funnel over 1 hour, and then maintained at 160 ° C. Then, after continuing the addition polymerization reaction for 1 hour, the temperature was raised to 200 ° C. and held at 10 kPa for 1 hour, and then the styrene and butyl acrylate were removed to obtain an amorphous vinyl-modified polyester resin [A1]. Obtained.
The vinyl-modified polyester resin [A1] had a glass transition point (Tg) of 56 ° C., a softening point (Tsp) of 100 ° C., and a weight average molecular weight (Mw) of 12,300.

(2) Preparation of vinyl-modified polyester resin fine particles 30 parts by mass of the obtained vinyl-modified polyester resin [A1] was melted and remained in the melted state for each emulsion disperser “Cavitron CD1010” (manufactured by Eurotech Co., Ltd.). It was transferred at a transfer rate of 100 parts by weight per minute. Simultaneously with the transfer of the molten vinyl-modified polyester resin [A1], 70 parts by mass of reagent ammonia water was diluted with ion-exchanged water in an aqueous solvent tank with respect to the emulsification disperser, and the concentration was 0.37% by mass. The diluted ammonia water was transferred at a transfer rate of 0.1 liter per minute while being heated to 100 ° C. with a heat exchanger. Then, by operating this emulsifying disperser under the conditions of a rotor rotation speed of 60 Hz and a pressure of 5 kg / cm ² , an aqueous system of vinyl-modified polyester resin fine particles having a volume-based median diameter of 200 nm and a solid content of 30% by mass. A dispersion [A1] was prepared.

[Preparation example of aqueous dispersion of vinyl-modified polyester resin fine particles [A2] to [A6]]
In the preparation example of the aqueous dispersion [A1] of vinyl-modified polyester resin fine particles, the vinyl modification with amorphous vinyl-modified polyester resins [A2] to [A6] was performed in the same manner except that the formulation in Table 1 was followed. Aqueous dispersions [A2] to [A6] of polyester resin fine particles were prepared.

[Preparation Example of Aqueous Dispersion of Amorphous Polyester Resin Fine Particles [A7] to [A10]]
In the preparation example of the aqueous dispersion [C1] of the crystalline polyester resin fine particles, the amorphous polyester resin by the amorphous polyester resins [A7] to [A10] was similarly used except that the formulation of Table 2 was followed. Aqueous dispersions of fine particles [A7] to [A10] were prepared.

[Preparation Example of Aqueous Dispersion of Colorant Fine Particles [Bk]]
90 parts by mass of sodium dodecyl sulfate was added to 1600 parts by mass of ion-exchanged water. While stirring this solution, 420 parts by mass of carbon black “Regal 330R” (Cabot Corp.) is gradually added, and then dispersed using a stirring device “CLEARMIX” (M Technique Corp.), An aqueous dispersion [Bk] of fine colorant particles was prepared.
With respect to the aqueous dispersion [Bk] of the obtained colorant fine particles, the volume-based median diameter of the colorant fine particles was 110 nm.

[Example 1: Toner Production Example 1]
(Aggregation / fusion process)
In a reaction vessel equipped with a stirrer, temperature sensor, and cooling tube, 2000 parts by mass of ion-exchanged water and resin fine particles for forming a core part. Aqueous dispersion of styrene acrylic resin fine particles [1] (solid content conversion) 288 parts by mass-Aqueous dispersion of crystalline polyester resin fine particles [C] (solid content conversion) After 32 parts by mass were added, a 5 mol / liter sodium hydroxide aqueous solution was added to adjust the pH to 10. Furthermore, 40 parts by mass of an aqueous dispersion (Bk) of colorant fine particles in terms of solid content was added, and then an aqueous solution in which 60 parts by mass of magnesium chloride was dissolved in 60 parts by mass of ion-exchanged water was stirred at 30 ° C. for 10 parts. Added over a minute.
Thereafter, the temperature was raised after being allowed to stand for 3 minutes, and the temperature of the system was raised to 80 ° C. over 60 minutes, and the particle growth reaction was continued while maintaining 80 ° C. In this state, the particle size of the associated particles is measured with “Multisizer 3” (manufactured by Beckman Coulter), and the shell layer is formed when the volume-based median diameter (D ₅₀ ) reaches 6.0 μm. As resin fine particles for
-Aqueous dispersion of vinyl-modified polyester resin fine particles [A] (converted to solid content) 45 parts by mass was added over 30 minutes, and when the supernatant of the reaction solution became transparent, 105 parts by mass of sodium chloride was ion-exchanged water. Particle growth was stopped by adding an aqueous solution dissolved in 420 parts by mass. Further, the temperature is raised and the mixture is heated and stirred in a state of 90 ° C. to advance the fusing of the particles. When the average circularity reached 0.945, the mixture was cooled to 30 ° C. to prepare a dispersion of toner base particles [1].
(Washing / drying process)
The obtained dispersion of toner base particles [1] was subjected to solid-liquid separation with a centrifuge to form a wet cake of toner base particles. The wet cake was washed with ion-exchanged water at 35 ° C. until the electric conductivity of the filtrate reached 5 μS / cm in the centrifuge, and then transferred to “flash jet dryer” (manufactured by Seishin Enterprise Co., Ltd.). The toner base particles [1] were obtained by drying until the amount became 0.5% by mass.
(External additive treatment process)
1% by mass of hydrophobic silica (number average primary particle size = 12 nm) and 0.3% by mass of hydrophobic titania (number average primary particle size = 20 nm) are added to the toner base particle [1], and the mixture is added using a Henschel mixer. By mixing, toner particles [1] were produced.

[Examples 2 to 10, Reference Example 1, Comparative Examples 1 to 7]
Toners [2] to [18] were obtained in the same manner as in Example 1 except that the formulation in Table 3 was followed.

[Developer Production Examples 1 to 18]
For each of the toners [1] to [18], a ferrite carrier coated with a silicone resin and having a volume average particle size of 60 μm is added and mixed so that the toner concentration becomes 6% by mass, whereby the developer [1 ] To [18] were produced.

  The following evaluations were performed on the developers [1] to [18].

(1) Low-temperature fixability In the copying machine “bizhub PRO C6500” (manufactured by Konica Minolta), the fixing device is modified so that the surface temperature (fixing temperature) of the heating roller can be changed in the range of 120 to 200 ° C. In the environment of room temperature and normal humidity (temperature 20 ° C., humidity 50% RH), the toner adhesion amount is 8.0 g on A4 size high quality paper “NPI 128 g / m ² ” (manufactured by Nippon Paper Industries Co., Ltd.). A fixing experiment for fixing a solid image of / m ² was repeatedly performed up to 200 ° C. while changing the set fixing temperature from 120 ° C. in increments of 5 ° C.
Among fixing experiments in which image smear due to low temperature offset is not visually observed, the fixing temperature of the fixing experiment relating to the lowest fixing temperature was evaluated as the minimum fixing temperature. The results are shown in Table 3. In the present invention, a toner having a minimum fixing temperature of less than 160 ° C. is determined to be acceptable.

(2) Heat-resistant storage For each of the toners [1] to [18], 0.5 g of the toner is placed in a 10 mL glass bottle with an inner diameter of 21 mm, the lid is closed, and tap denser “KYT-2000” (manufactured by Seishin Enterprise Co., Ltd.). ) And then left for 2 hours in an environment with a temperature of 55 ° C. and a humidity of 35% RH with the lid removed. Next, the toner is placed on a 48-mesh (mesh 350 μm) sieve while being careful not to disintegrate the toner aggregates, set in a powder tester (manufactured by Hosokawa Micron), and fixed with a press bar and knob nut. After adjusting the vibration strength to a feed width of 1 mm and applying vibration for 10 seconds, the amount of residual toner remaining on the sieve is measured, and the toner aggregation rate, which is the ratio of the residual toner amount, is calculated by the following formula (1). This evaluated the heat-resistant storage property.
Formula (1): toner aggregation rate (mass%) = {remaining toner amount (g) /0.5 (g)} × 100
When the toner aggregation rate is less than 10% by mass, it is judged that the toner aggregation is excellent, and when the toner aggregation rate is 10% by mass or more and 20% by mass or less, when it exceeds 20% by mass, it is difficult to use practically. It is judged as a failure. The results are shown in Table 3.

(3) Image Glossiness As an image forming apparatus, a commercially available multifunction machine “bizhub PRO C6500” (manufactured by Konica Minolta Co., Ltd.) is used. On the transfer paper “POD gloss coat (128 g / m ² )” (manufactured by Oji Paper Co., Ltd.) in an environment of normal temperature and humidity (temperature 20 ° C., humidity 50% RH) with the surface temperature of the heating member of 180 ° C. A solid image with a toner amount of 4.0 g / m ² on the transfer paper was formed. The glossiness of this solid image is measured using a gloss meter “Gloss Meter” (manufactured by Murakami Color Engineering Laboratory) at an incident angle of 75 ° with respect to a glass surface with a refractive index of 1.567, and the glossiness of the image is evaluated. did. In this invention, the case where glossiness is 65% or less is set as a pass. The results are shown in Table 3.

Claims (9)

A core-shell structure toner particle comprising a core portion containing the first polyester resin A and a shell layer containing the second polyester resin B covering the core portion;
The second polyester resin B has at least a metaphenylene skeleton,
The second polyester resin B is an amorphous polyester resin formed by bonding a vinyl polymerization segment and a polyester polymerization segment,
When the content of the metaphenylene skeleton of the first polyester resin A is a (mass%) and the content of the metaphenylene skeleton of the second polyester resin B is b (mass%), the following relational expression (1 ) For developing an electrostatic charge image.
Relational expression (1): 0 ≦ a <b   The toner for developing an electrostatic charge image according to claim 1, wherein the first polyester resin A contained in the core portion is a crystalline polyester resin.   2. The electrostatic image developing toner according to claim 1, wherein the second polyester resin B contained in the shell layer is an amorphous polyester resin.   The electrostatic image development according to any one of claims 1 to 3, wherein the metaphenylene skeleton in the first polyester resin A contained in the core portion is derived from isophthalic acid. Toner.   The electrostatic image development according to any one of claims 1 to 4, wherein the metaphenylene skeleton in the second polyester resin B contained in the shell layer is derived from isophthalic acid. Toner.   Difference between the content a of the metaphenylene skeleton of the first polyester resin A contained in the core portion and the content b of the metaphenylene skeleton of the second polyester resin B contained in the shell layer (b−a 6) The toner for developing an electrostatic charge image according to any one of claims 1 to 5, wherein the toner is 4% by mass or more.   The electrostatic charge according to any one of claims 1 to 6, wherein the content b of the metaphenylene skeleton of the second polyester resin B contained in the shell layer is 4 to 16% by mass. Toner for image development.   The toner for developing an electrostatic charge image according to claim 7, wherein the content b of the metaphenylene skeleton of the second polyester resin B contained in the shell layer is 8 to 16% by mass. The electrostatic image developing toner according to claim 1, wherein the core portion contains a styrene acrylic resin together with the first polyester resin A.